Field of the Invention
The present invention relates to a stapler capable of stapling a workpiece using non-metal staples.
Related Art
Conventionally, there has been proposed a stapler capable of stapling a workpiece using staples made of a non-metal material which is a soft material, such as paper, instead of metal staples. A stapler using metal staples is configured to penetrate the workpiece using a staple element, but a stapler using staples made of a non-metal material which is a soft material, such as paper, includes insert blades for forming holes in the workpiece, by which the workpiece is formed with holes by the insert blades, and leg portions of the staples penetrate the holes.
The stapler including the insert blades and using the staples made of the non-metal material which is the soft material is configured to hold the staples between two insert blades in a state in which a pair of leg portions of the staple are arranged along each insert blade, and to drive the staple against the workpiece together with the insert blades to allow the one pair of leg portions of the staple to penetrate the workpiece.
As a configuration of holding the staple at the insert blades, JP-A-2002-168216 and JP-A-2007-167978 proposes a structure in which a boss for holding a tip end of the leg portion of the staple is provided on an inner surface of the insert blade.
In the structure, when the boss provided on the inside of the insert blade passes the workpiece by an operation of the insert blade penetrating the stapling blade and an operation of the insert blade leaving from the workpiece, a resistance between the insert blade and the workpiece is increased. In a stapler operated by a human power, if the resistance between the insert blade and the workpiece is increased, it causes a load to increase in push-down operation and returning operation of an operating handle.
Further, when the boss provided on the inside of the insert blade passes the workpiece, an inside of the hole is torn off. For this reason, when the leg portions of the staple are bent, there is a convex portion causing the leg portions or the like to deform, which deteriorates appearance of the staple stapling the workpiece.